Rivkin

Everything's possible, but while I've seen koto plenty of fakes, in particular Bizen school ones, with convincing and well executed signatures, I admit to not having experience with a chujosaku shinto gimei where the writing itself would not be problematic at the first glance. But the proper way is ofcourse checking the books.

The signature is well done, so even without look at books I suspect its genuine.

I think in searches the first results are tilted to be the most heavy-traffic sites. It works when you are in newspapers or wikipedia, but otherwise can give some weird results. Danny is a fine man.

Ambitious, at this price level Juyo papers would definitely help matters, otherwise I don't know how hot the interest will be. But that's one of the better if not among the top tier of Muromasa's. Bright, vivid jigane with ji nie and ara nie, strong hamon, absolutely classic Muromasa style.

Japanese tradition tends to attribute the reasoning to something utilitarian, I personally doubt it is often the case, compared to economics/material availability/fashion. Same is very hard and water resistant as is and it survives for many decades without any treatment. I feel that black lacquer was seen as relatively inexpensive methods to improve appearances; for example, the original statement regarding the need to have black lacquered kashira at court did not see it as modest, on the contrary it alluded that people use varied kashira with varied (i.e. natural color) appearance and that detracts from court's decorum. Black lacquered fuchi, kashira and same would be a vast improvement in the time when shakudo fittings were something uncommon. For white same I am not sure of technological process, but I assume it is either boiling or bleaching-like and I doubt any lacquer is involved. There are cultures in which same is polished down a bit to dull the structure of larger grains since holding same without ito can be rather unpleasant; this however is less of a concern in Japan since its same is naturally less "sticky-out".

Nakago photograph, boshi, some macro shots and there is a good chance we can form a decent opinion re what it is. As of now the waki looks like possibly late Muromachi example (deep sori, hirazukuri), but I am also interested in katana - there is some potential here.

Very low resolution, I literally can't see a thing.

I would argue it was blackened in Muromachi, but a formal tachi same was at least often white. In continental tradition per images it is white.

I am probably the worst person to comment on the nomenclature since I have very little interest in it, but there is an inflexion of blade and koshirae classification. It is mounted as wakizashi so as it is, it is wakizashi. The blade itself in shirasaya I would simply call naginata and calling it wakizashi would be unusual. In a sense it is how the blade is supposed to be used as a weapon that affects the proper name. I would expect someone to be more knowledgeable on this, but I've seen a number of tachi where essentially only the final portion was somewhat reworked-shortened being called "ubu". I' suspect that as long as nakago retains the full signature and 95% of its original length it is in koto case can be referred to as ubu.

Internet shows in 99.9% "regular" Soten school stuff which is not the first generation. Books do show first generation's shakudo works and most are not what one would imagine them to be if internet and sword shows are the sole guidance. The school then continued for a considerable time during which it produced more or less the same lineup of items, mostly tsuba, in various quality grades. It was consistently popular, the items were consistently signed as soheishi nyudo soten. They were sold throughout Japan, and very common in certain places. Shakudo was always a more premier and rare kind, but no, this is not the best shakudo Soten I've seen. Its also one of more typical scenes, the really great work tends to be a bit more imaginative. But its definitely in the top 25% of shakudo Soten and top 3% of Soten overall. Nevertheless I personally don't see anything pointing out the first generation. These tsuba were made in significant quantities over very long time. We have no idea who were the great local makers aside from Soten's immedeate circle because they all signed in the same style (i.e. Soten), no dates. Such tsuba maker would be trained by the school from a relatively early age to make tsubas like this - obviously they do tend to look alike as well.

Depends on what kind of authenticity is desired. The founder's work - unlikely. Higher end school's work - probably yes. Sothebies considered circa 1875 which is Meiji, so their belief is its even after-school imitation.

Well, shakudo Soten are rare, especially daisho; this one is single by its still uncommon. Some argue they are seldom of any association with the Soten himself (at least in this style), but they are great examples of the school. In the US at a show the minimum price will likely be 2,000, maybe 3,000 USD. The top is basically determined by whether you find an interested buyer. I once saw an example which sold for 8k, another for 10k. But I would not be sure these prices are repeatable at ease.

Destructive testing. Probably the only serious way to go, but then ofcourse there is nothing to destroy between the end of Kofun and late Heian, so one should rely on Asian data instead. Availability of items for destructive testing is what limiting them - couple of Muromachi pieces, one or two before but plenty of Edo items. I liked Kimura's data but that's pretty much how many pieces he worked with. Kamakura there will be very few opportunities also, probably ko Naminohira is the only thing that can be haid that is not unreasonable pricewise... Maybe some late Kamakura pieces.

My interpretation of the old swordsmithing process is its basically adaptability to the fact that any bloomery, tartara in particular, is going to produce a very large range of material properties. Small portion of the load is going to be relatively perfect sword-ready steel. So you either go into piece-by-piece refinement techniques like they did in the Middle East or your forging and heat treatment has to account for the fact. It can be banded structure, it can be multi-layers. There is analysis which clearly shown multi-layers in more or less all Asian swords from the 10th century, but then it also shows that some forged from just iron, some had an opportunity to select specifically steel, sometimes you find some weird admixtures etc.. And each one of them adapted heat treatment - old multi-layers will always gravitate to narrow differential heat treatment of suguha variety, but with other compositions you have other options. Problem of Japanese scholarship is they don't read nothing of this, they follow Japanese publications based on testing like two or 10 blades from the entire history of nihonto and make a big conclusion out of it.

I don't have the article, but the first question I would ask is how they measured content. If its XRF I would take it with a largish grain of salt since its a fit, and most companies producing testers worry a lot more about expensive soft metals than inexpensive iron. Its very common for it to shown considerably more soft metal in iron then there actually is.

It is most likely shinshinto. Nice blade in Hosho Yamato style, by someone traditionally familiar with it. The only reason I would not say Kunikane is there is some notare/midare, though it is not clear how much is hadori and how much is real - polish is bright but actually quite bad, shinshinto blade in this style with nie should look more crisp and less hadori suffocated. It probably had a mei to Hosho Sadamune. Why someone decided to then refashion it as Osafune specifically is a bit of a mystery. Yes, nakago was likely artificially reworked to make it look ancient, such wild deep cavities can be produced with acid, fire and other violent methods.

Sugata wise it would be 1570-1650. Hamon is one of stranger shinto pieces, greatly accented by hadori. One of the issues is that hadori clearly goes through the actual hamon, so part of it hangs out outside as "ara nie" and part is within hadori. Without it would have a more "hitatsura" look, though still unusual, but might actually be not that weird-shinto looking (but I would still vote shinto, 1620-1630). Bungo did make a number of hitatsura and hitatsura-togari-Bizen styled blades during this period, some more unusual than others. I can't comment on signature since I don't want to go through many books. Unfortunately, Bungo pieces were faked from time to time, strange as it is to modern people who were driven into "bungophobia" by shinsa panels. Unfortunately Tomoyuki is one of two names most commonly faked, though fakes are uncommon. The placement of signature, the depth of strokes are consistent with the school. The execution is below to average.

This is above my paygrade since I am not good with early Bizen work, but here are my personal thoughts. The good: a. I think its really good polish. Polish above shinogi is unusual intentional choice, but I think it accents the steel very well. b. Definitely Kamakura Bizen work and around 1240-1260 can be an appropriate guess. c. Work style is a decent match for Mitsutada. The bad: a. Unusual sugata for Mitsutada. Kissaki in particular has much "longer" proportions then typically seen on his, usually conservative, works. Since hamon width does not change it does not look reshaped. b. The signature sort of ok, but not a great match for his most well known examples. Enough to give it some extra thoughts.

I don't think its 100% specific to a particular school. Without looking at books to me it looks similar to what one finds on Monju Yamato Tegai. The blade looks interesting. I am getting some late Muromachi vibes but this is obviously a pure guess.

The patina looks older, maybe later half of Edo, Meiji, but these things can vary a lot. Meiji I think is an option, as is Bakumatsu, but I am still more comfortable with WWII piece which for some reason aged fast.

Yasurime is of late type (shinshinto and later, though yes, there were some Kanbun examples supposedly worked like this, but its exceptionally rare), it is also done very sketchy - the lines are not parallel, the cuts are shallow, there is not forceful look expected from shinshinto, it was not patinated when finished and since then though patina is present, there are areas which remain patina free. I vote for WWII production.

Yes, sugata wise very close to Kambun... I would check if boshi is sugu for confirmation.

Yes, it does look like one of Tsunahiro's generations or someone very similar, Muromachi to early-mid Edo. I personally think its Edo generations.

To me the most interesting answer is that they are virtually unknown for pre-shinshinto blades. In books samurai wore a pair during the entire Edo period, but it seems like pair Tsuba and pair blades in 99% of cases begins roughly with 1800. Otherwise, they are rare even for shinshinto.

It would help to see the entire blade, sugata etc., but so far it looks like a nice Tsunahiro.